1. Field of the Invention
The present invention relates to an airbag device including a bag-shaped airbag which is, when housed, folded into a folded-up body having a generally rectangular parallelepiped shape, and an airbag wrapping member mounted around the folded-up body to keep the folded-up configuration.
2. Description of Related Art
In the prior art, Japanese Patent No. 3467114 discloses an airbag device including an airbag which is folded into a folded-up body with reference to a straight base line running through a center of a gas inlet port along a plane of the inlet port above the inlet port. The folded-up body is formed by, from a state right before completely folded-up configuration, bringing both ends of the airbag extending in opposite directions from the base line, close to the base line to butt against each other. As a result, the folded-up body has a generally rectangular parallelepiped shape symmetric with respect to the base line.
An airbag wrapping cloth is arranged to wrap the folded-up body with its both ends in a direction perpendicular to the base line secured to the airbag. In a position of the wrapping cloth correspondent to the base line is a generally straight breakable portion having intermittent perforations breakable upon airbag inflation.
In a conventional airbag device, however, when the wrapping cloth is mounted around the folded-up body in a condition that a butt portion of the ends of the airbag, which is to be disposed proximate to the base line, is deviated from the breakable portion of the wrapping cloth, the breakable portion is not likely to be broken smoothly upon airbag deployment. This is caused by arranging the breakable portion straightly along the base line. Moreover, some folded-up bodies have a butt portion, too, in an internal position thereof, where airbag portions are folded to butt each other close to the base line. In this case, the position of the internal butt portion is not easy to grasp from the outside. Accordingly, there is a challenge in improving accuracy in making the position of the internal butt portion of the folded-up body generally consistent with the position of the breakable portion.